SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c48b8178ba9e88cab59440c036e344619e0ed01511e8b8abc0a79d206056e6ab' 
  AND token = 'xPL2NPnmmXf1dRUoAbrOPjj4Au9rQp/QHb//aR6KD74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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