SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '142d9beb8f5e5c2b1dd25ec013d0a4774d2b7afa8840b1564f3188ad01116a89' 
  AND token = 'bcWfxyA006qI3RbLh3DBmtuYUmhnGqCCzreUk1jrJkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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