SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '371559fed8b8ce4275c6e58dfe9fd1a8bf257af64893c0ff9758b7685f4c4167' 
  AND token = 'ytEMPwtpdkdSn8JP3ccFcLFqrw2VJYdHeE4lEZWkJS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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