SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1e2f3b550cc016f0ba0f2bf3c2d27a97e3471adcae1b30e6b094dc22b41e658' 
  AND token = 'qJjnbMKk0fwufFVrMF7CXuz3j0KOUr3DQWWubNr4HJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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