SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f109798ed98f6749cac27e38e4b023d080ea8c1c17e6b50c53f238f2cc4be34f' 
  AND token = 'h5yKjcTKusSTpeMkLJQ/WpB67Zq/CcCoBShgg/Rmytc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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