SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1263e81f88b95cad553f7e9f943d1a7c3a79b74b5bfe494a33171a1883fb7699' 
  AND token = '8PAhgTyNpdmmeoGoAAOxZVeZF2SQ/jn2ooVKiRSuBvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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