SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0abc3dfed95e1dfbff791c130b52534773677731c7d822437066701062a6d79c' 
  AND token = 'WAXkmv2xgn36R1lK6GJgjoT9eD3ZnWNAudqBieVqDpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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