SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cfb916868d14c7b7e556553c12dbfd81759f28a9de06c046046571be7f508b1e' 
  AND token = 'yk0SOBTdTPLFW0M3jeCk2MYrmrl/xWX6jQLyCAPlD58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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