SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e1068d76264318c361eda45de0126fa633ac8c06c7b243ffa120993ec0fc0c0' 
  AND token = 'xBJBRCKguDWMqJS+qKQV3/xmFRUYVnLIpF5TuzobzD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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