SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e30f09e8f6736035d5ecd765cc4daba8f217365660227306747edbe498a37a7' 
  AND token = '9Pk2/gjcl7jze3Px4uDkRUyTwsR5m3cU5EPr/cwRgDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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