SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebc3de917f917ccf54a3f42acdcfaefa18e8c1df9c647178042ec92d906017db' 
  AND token = 'RTx1z48ZNvrLvrta3Ptt6SwEI/JIztL1JzJIASlr6Ng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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