SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4895de1dc0d8058681f0c43cf4728a1af08765baeb8917f92e97a08b0976f1ca' 
  AND token = 'BRcFU8TLcB1qEvYlFr+JlAg0lEAocgXOj6xgWzXDwJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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