SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54c9260b5b67788092e718bab659953c415f631bd9eaa242ae05ed8ba9f0a474' 
  AND token = 'oVdHU7kLWzUeun+/eCfQyBvcTvLcIwndd1Nrgv+u4ac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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