SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '312a1486f9b667df4d66330f01fc10eb2c5e61eca1d788df5761b9ed642b8aa4' 
  AND token = '9GmGGpEUmqKuABpc8I3UFCoLzokfuX7lxBW/3WRJh6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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