SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94f76c59fe12bd191dd4027b583f74f7e969496518f955026239e4cea91b4f81' 
  AND token = 'lh/HpxuW5YGIYYbjEyDTinc0Y0HFrnBaf15T5uxcqAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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