SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5a3030361f35613409e34259046293d96923297839e9b64c21650844bcd2d43' 
  AND token = 'sC63dFCacHAOZxWgaMBMKqtFkCBWlJxOzljl9nY7hDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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