SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49c675d5b426da3cebb7cc870de0352cab7e982971817290616f2aa2af012707' 
  AND token = 'yde+Ko2WYDVRJU5g8l6bTgQ3W4OCYgC6kUHyJtEWGJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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