SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '896e0ab5aea7235af0fe86350f778fec872b47848586837813699aaa19c84da3' 
  AND token = 'Mh6pUIjNgchnKIjpN6sY0xQWYceIJncKBXK98lSfrW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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