SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d4905a51e99803fc277ff53319e809a3961693a517fec86208a4136ddb48795' 
  AND token = 'Cxc+Hp5ZP1ZU2UiGXYiWDk+6lovaaBwYLmFB6Q5p1IY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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