SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '615e0913db5b92abc2a26fbb65c995e94200661c2b33be112d1b59a0bdb75aa7' 
  AND token = 'fqEKBBP95UBDa/QbNLnlFRr0gRMQ48le1Kt5mT29AEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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