SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff41cd20bd52f423056c6a13f3fdd941709c3e0325a5104d641cd3cd7990063d' 
  AND token = 'H4JAZ/HhLEjrPZ8C1iMxGGDvjEUfXsCWIU7P/z3Vplg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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