SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcf3e88c77f7139910b3b0b5036a63598451594cfc41ece6501ed9312cca31ea' 
  AND token = 'BdMiqAFh5SNJv6tbt3zJ6cV+aJ8/eosp9to/HeWSOX0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}