SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fa06d1b73292c62d6a441cd64ae1d05d93ac23014f529654f385ca715b7c539' 
  AND token = '/OHLbIptKXVJGL2IWEFGaCqhj46n801osTf/ArHKy5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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