SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47c421f8459872b9bb23e4bab59491d7751d8eb23f4cf44687dee91a19de9ba7' 
  AND token = 'OBRvN3jquW1k5kqWP7Z2KwOA/pUujrE/VFazqiKDTCo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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