SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0b681ecabb8ed843af63d6c0676e38fceb33d09f5d239fdbc624bf3cc2fe895f' 
  AND token = 'lCWhIQDr4OaNlcGvjT2cHr/I+KznxG8oE2w2MvLhNwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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