SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dded79690114ab5733752feb29d147926cd693e499eff5389f5e1b19fc5219a8' 
  AND token = 'iumYraZjsgoQzrVaO5uEWdVL9hucA2iqRytT5Kyyz4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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