SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9ae983798c0099b697181ab81db200ac478906e514891fa468e9a3d500a098d5' 
  AND token = 'FSdur36o45Q1LzRNpsIuwtJOdJfwC+u2e5zwSn4Pnj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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