SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '626efa93b5e090bff65f813b34274615fc17f30d5930c9be22e3466c39091ee7' 
  AND token = '8Lg3motOmE63zWjQwep7JI9G3BoW4GnWNGsloKoElAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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