SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2f751f2fdb3439285efc4b96588395c3a9b51cbad6c549279b9d7ea4229085b' 
  AND token = 'jJTgGv+Lm7TQLkyvlhHttbYHCvNTb9/+99PNYl8itYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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