SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4b20dd3377b87b14b675ef683c53cb4de6f7e813430c1aebf9ad373cae622462' 
  AND token = 'cuTwY6jFnvAeGp1YbTxY6CTjPwROOfmfCRDvlKxwD7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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