SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68a987220db24a84c147e8fd04eea329e67dc357d81b02533486783631b3c985' 
  AND token = 'aSInrRy/O7CCvLiwFj6JGI4+KgLY4x9Yue7ImQioBes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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