SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3a8afeb3220e94c12a58ff6df26ef0efddf9254ccd219dadf64e270ceb763e1' 
  AND token = 'pMbhlucsQZ6sdmnhGuFqisenO0yrBohqkIMkHSde4TM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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