SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6049d61fb70c7226e69df6573cae3a49a1d941dceb45067f9098b4a4ea6ac83' 
  AND token = '8Wvfjrbw2Io1UIPqz33QBYhlW485bQeJfKiBcbjF+vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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