SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ec87936b9e8091dccf1fb53acab6e65d983a42b738e98cb5535cbb34fc78881' 
  AND token = 'K28M0qtUbYU1TJS/W8V6sXd3zCiaXNWUG39oz0DuNzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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