SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c5d7c28c5525d94a3f0181d0c2f488ed530dd8f8bb31f3cedefbc0529aa13cc' 
  AND token = '4F+lhQIK/xfrIYjc4QrQnt9PRpheVxwpZaCJDWg5ums=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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