SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91729516a68045afa631db050ff9934d1be26ce79d9b076189b0872652da2282' 
  AND token = 'hdYxdA6wHwBQRqlT6yYYSEGgvT3y7v/LrRshCPkObL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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