SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7368eac204b43456997f2192114de81b7959934e4f0d560db97bd248397584e4' 
  AND token = 'scjfvTgd9pcOCUb3emoissc5YOaXsTDFX+UDQRFrZ/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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