SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f27dadf761e51814a83f4895566519942acbd40939ce11d8ed2fdab46852aaa' 
  AND token = 'AxinQmLVC6UW77HTCJKzcLsFAwnl/QblFCMjfCZ+leE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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