SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cf23e19d7f83ba8bfec7b7c0bead289542a9ffd9c43822c2113272b46b7a255' 
  AND token = 'MK/Qivfo7WqG3+Ak0gYihwqWCh0sjpKUOeIMk/1bGV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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