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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15bacbe27f9050f139da018603f7da19017923262532d0537f3c660d8e87f8bc' 
  AND token = 'mfqNqEqiz2b77mI9CbJuVxAjWrT3aB/iZLmFWIlHdn4=' 
  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"
    }
  }
}