SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16ce59eeaffc832afe767a43861c64a6ba4bcc8afa12ad0e7f33552ecb246894' 
  AND token = 'o2XiVeySnKz7NZbBd6sE/j5Ef3rMKgqE4rzEE1qyPGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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