SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1e29801c638a14f415e24d3a57d85987909fbd10ae10d443331b7b134513ec4' 
  AND token = 'hn2GBEHaHtlWgO4n3ysVswM026asyXhIH2sSXjMfV64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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