SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ba994994830530afa7a755502784867467b8956d4063abf9b7cbba94045cb6f' 
  AND token = 'yMUUTZ/wcJzPOxzDIZqPv4v9p3NN74gT4/OSzdWUQqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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