SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15230c086723c16fc3538259c9db14c444ddacbe093a838578a658a1b2e30889' 
  AND token = 'OJUvcx7yRqlChc0p3H4UEask+9GwlvElt2lFlLMMkLA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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