SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34fb09219410e0d2d0011785e94a3017b336c38c3e2a507639bff0e43cd6fc02' 
  AND token = 'zZkA+QL4r9JuvhD+jMOfYdy4Qjy6wnJ853d9sfHxL0c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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