SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b873f37b6d7b0136dbef6c77b7330ee6683e38f8077d9c09ef568ece4657f789' 
  AND token = 'lrEsTg48yELADaGJyTPhegqsDVQO5jDskmZnuNwbGbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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