SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e9796384770358496c5b368e47623f282db3a79fb516ea7468eae45044683c0' 
  AND token = 'MlnK6EBN7Fzke/p28ksUnbH4fM9DMgp3kNEI8dRkw7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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