SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a49fab89da75a4faf584fb463df4feb10d8c49d886d4e867631e92f14a0b12a' 
  AND token = 'WCW71yEWpOtGCR9QI9rX/DJtFea94jVYtBNLILhcm3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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