SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b700ae83af1256772d93f0c76ce1a1242a445732aaa23820b25a9259ccd46a47' 
  AND token = 'afyt6Ybv/eryqgQqXYW4I/I3cDev5ThgtCYCv7wC7Gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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