SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90fe2e762ba0fb3c6919184b3e38f6f95982c29bc7a305594aa5d966773a7145' 
  AND token = 'amy/Ztz1iCIZNOwZiL7JNG5PfRkeEzAlDYeNtTxmJOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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