SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f0cb54845e594913b6ffba24e469cddc79d58fa67d7c36b6ca7d84799f27312' 
  AND token = 'MAWRhsRMSmeLrMHH72NBqXiF5Ws6aEORUYePfluiMNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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