SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '957ce5c456946f62ae6f33baddcca05dfe091f062a29148ce8876302471b3544' 
  AND token = 'io+KSJxfN2c3YckycRLLpCbZHutK66rPfBeZSXb4nzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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