SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c6125f2485db54e21e1b8a5d0b3d2f3173aa344c6fd6737dbd61855a51b16b8' 
  AND token = '5Jk4o0fXKP5St5s3Z2B7eFjOdQ1KAOYmeGtpF+EIojU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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