SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eb26b8a50d48b2e6414dbd9b38b9838c0c998dd55b20a56161ef4b91b85d265' 
  AND token = 'EVmdaBiufchTsHlbmsCnHPYBFEhyvSYSUYS8Uues5eI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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