SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd790ac8194bd4988469b054093745c93586f93f47fe6097967e5a1a01854a34' 
  AND token = 'R3JospYqr/XfBGRPJFEgSESZZt2Whwi+1KbBtkfA5SE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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