SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6313fc871b31ec4798a7ff3e45c829e3c866dd562277a4e49dbe412d08c623e5' 
  AND token = 'oNlu8LiWFLtDPQKVBk7gQlGcKwV4Cwck4vwhqhsvPRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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