SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f115f7ec176ab0b2ada0444578ff05f1dfe63b912705bf6d8292cef97b4489ad' 
  AND token = '2Yhpp9uWI3s0c/ApzhG8Fz5/f3vXj6OvlP9Czvyb6mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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