SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '936258c164bdcf99c16d9581e09abae75d38a0487acbac55a7246028f13258bf' 
  AND token = 'I8qipomCxE8Dd1oXUfExUuPVg8H2ta3LV37SyomuX4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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