SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb78a4f88fc94acf4158f2a2217eb893754aafb87be5a329b2cb8018aced53ae' 
  AND token = 'm8NEGWoNbA1YrF+/l3BIaqq4DRjseuq6JhKLg3tMKWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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