SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23db78bb7093b400dced8c25352b4b9acabaaa10e55bf67061b316126ce28037' 
  AND token = 'PWyp1978l5ixCcJ4rrOOsE2wsHjJTSnQolkRrF/qcF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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