SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9aa2fb435adb5679778ea1682df6ed03926a525e97d5893bbd0c15268e39da57' 
  AND token = 'idWShHxy9OVhBoIVSVPDk7ac4+uCLVZTG1JjW84IVsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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