SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3f40b51097bdf07d60d003153cb4194739637352d54b1d72c6bfdb227742965' 
  AND token = 'ev9m5+jUSBf3EHD8WbvZtNh4ifxUFqlq5rLuAVIe+8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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