SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b0c48e34ae7134e67ecd073be0477c6534da3fcc74884e4da4a3f77c1dd0b57' 
  AND token = 'YbpWhZWUdKnQfuFTEm7kVNXVRYCH/QPffDSVoh5U7tg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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