SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c6f5fd3b9555003a5292054b46dd22af419c2ee2053dc5c66371b4042bdfe85' 
  AND token = 'TPQFfIQjYkDuzhaBJfKYwcFPelFUoqcvXp5sIIy0EKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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