SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e864124e5825258bc53efba3108d4aa7ebdaf91676eb8e1171d45f47f088fc1f' 
  AND token = '6iKIL+FEfIxTFuBM4NnDbFE0TFPD6Hyh9YBeUYefZaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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