SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e43542d4c884709c0f497bd27aa9394030c5ee348924ff1ae3feac0a049e9e8' 
  AND token = 'Y+mJfjV1eUnA5z5KfViR2kMPjOYqqkwCjxr9IQxsGxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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