SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '527aad7c28d597c4441228bbece6b06f1498b7c06121caeaec6925bbf6424d40' 
  AND token = 'KJOoYc06IUgocFUCgFnm2Wf0IG/cYcwHnWn7K4TOtec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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