SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '073da2d15e6396aca889e0f3c4761c9ec58620acdb95e6365d4e60d4ae60fff4' 
  AND token = 'Cx6JTwSXBLkJ5NmdFRnT/k3dVqSLaXTu0CDBcvFnoEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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