SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4bfd24872c5f94d229ca866a966d0bf3cdb85ccae6c9cd2dd4612583fd03e53' 
  AND token = 'YlvyIY3rIIWstl5uIVAIiSur1ZrDqgLX5oI5mBrS4wM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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