SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac205993dc04892e1a688ee50b49accc69969a6deb79e8d547ca5d0d29e62c7a' 
  AND token = 'MXGM595FqHShyoakFupj/s2vq5GRY1xouywnpMfXwT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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