SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '779f2ad4de504d80ad38a9fad74a3218a4a861d9a4f28434e21b587ce208ba38' 
  AND token = 'mGXX50y6DkBQiZi806UUJScJfv8PsFmK+mNEruaoKGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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