SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43f9f58c2282e58b7c76aa9e107d8af23b58c45cb5015044bd75227768ca030d' 
  AND token = 'eFhu8fb4lnSYwxzsfWcSzEY9tZujwYVMMM9srgw+Zck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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