SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '81d0b897c8e534a3421e2e58f4366c3793f1ebb7c8a6be7a5345d99525267d1b' 
  AND token = 'tJgYTukn1HuCcAtOxRtoNn4gQxxa5cuvgIkW1DDn7qA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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