SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d3ea2cd187929d5e4dda3cbccdad76b0f42ea975c95591860fbe141a16cf0db' 
  AND token = 'iPykRqjaWAMCDcTm/hv2dNxmB5de3gTodJ4CEzGZZLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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