SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58ac356482d736267f5457e6664826938ecd36647c9dcea06f40d12eb12914cb' 
  AND token = 'An5JjcimPdqcfMoS245ppd4L9udA8ma/jPkeWQJTV84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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