SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c1e0e11be85730a5e5ef3acf94e514363e0775439f5753fae5d449d219d802d' 
  AND token = 'y15wBx/MhtCOnsch9GY6aT4ddVZK3o9Y2nAKXZHkRKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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