SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd88616a91faade37cc4f595112f04c39c0ef21013764010d4999dbce486b27a2' 
  AND token = 'wqllye2SUMb8U/55uIkWGk/MhJ0zKRCjC9uBM5uX/0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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