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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '939fb3f8ce393eb10f3e750d2d67203b0d0b03dd4db36bb92c467a29b7e2f648' 
  AND token = 'a413fB2NTwV/2qLzuwjGI8NubQfkt/eTe93kuBFKRTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}