SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1185bca559956b7c90c08a615d62902fc9100644c2754db04c8947ddf2127b65' 
  AND token = 'yBgPh43uRbhkscJriqveSe9elpQicdwPCjiPNt4LsOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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