SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ae037834b4da094772017c88d10e61e79d7be4dcd391c452ceae6f2c5e81ae4' 
  AND token = 'JhYJ7RYT7HYLfq6cnCYBu0qVsC3kHfYZHbrhpUsZ/Qc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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