SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c64b5707c6b0097a06c46ae182a35fd74f00f25a68a65fb8940e767ea98c513' 
  AND token = 'beiynzetJzEKSq7ww4QTu2058iAJp+PeFcndfrMw6NI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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