SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe0d1ade427c6695a802ca2757bf7506b346f113fe32f16b7d7dc088f83bad59' 
  AND token = 'l+JJiYNExf7aP+fypqsWH8vx+LQOvoWnInORU1Psq8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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