SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed68c4a762580e079768f6830981a20374a3149076f16040ccb4ac1ed695ad52' 
  AND token = 's88o7rKcPdsiTNNqIsYTJG48547caYDeR0mamAoqH5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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