SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f3b7b68903b599b765e01695d89adb384993472367ed0a4dd68abd0cb3cefb81' 
  AND token = 'vRLCG1TucAi6VWVgsg394aVAbn+XQl05guLzDZ7GJFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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