SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf261becba2521a6a95dbc16f66f9c00e7620e4091765360e789b80ca81673b3' 
  AND token = 'RftzXS/AaiFgJzRa5P09FK4FJqZnr6GS4cd1KF5Laq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}